---
name: "CURLMOPT_TIMERDATA"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLMOPT_TIMERDATA"
---

# CURLMOPT\_TIMERDATA(3)

custom pointer to pass to timer callback

## NAME

CURLMOPT\_TIMERDATA - custom pointer to pass to timer callback

## SYNOPSIS

```
#include <curl/curl.h>
CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_TIMERDATA, void *pointer);
```

## DESCRIPTION

A data **pointer** to pass to the timer callback set with the *[CURLMOPT\_TIMERFUNCTION(3)](/CURLMOPT_TIMERFUNCTION/3.md)* option.

This pointer is not touched by libcurl but is only be passed in to the timer callback's **clientp** argument.

## DEFAULT

NULL

## PROTOCOLS

This functionality affects all supported protocols

## EXAMPLE

```
struct priv {
  void *custom;
};
static int timerfunc(CURLM *multi, long timeout_ms, void *clientp)
{
  struct priv *mydata = clientp;
  printf("our ptr: %p\n", mydata->custom);
  if(timeout_ms >= 0) {
    /* this is the new single timeout to wait for */
  }
  else {
    /* delete the timeout, nothing to wait for now */
  }
  return 0;
}
int main(void)
{
  struct priv mydata;
  CURLM *multi = curl_multi_init();
  curl_multi_setopt(multi, CURLMOPT_TIMERFUNCTION, timerfunc);
  curl_multi_setopt(multi, CURLMOPT_TIMERDATA, &mydata);
}
```

## AVAILABILITY

Added in curl 7.16.0

## RETURN VALUE

*[curl\_multi\_setopt(3)](/curl_multi_setopt/3.md)* returns a CURLMcode indicating success or error.

CURLM\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLMOPT\_SOCKETFUNCTION**(3)](/CURLMOPT_SOCKETFUNCTION/3.md), [**CURLMOPT\_TIMERFUNCTION**(3)](/CURLMOPT_TIMERFUNCTION/3.md)